More Than a Glass- A Broader Conversation About Cancer Prevention

Article By Dr. Donald Greig

October is Breast Cancer Awareness Month, but cancer prevention should not stop at the breast.

In my practice, a diagnosis of breast cancer prompts a broader conversation about prevention, including bowel health. Equally, when a woman has colorectal cancer or precancerous bowel polyps, I take the opportunity to review her breast screening and family history.

I offer my breast cancer patients colonoscopy screening, with an individual discussion about its timing, benefits, risks and suitability. I also offer my female patients with colorectal cancer or precancerous polyps appropriate breast cancer screening. This reflects my commitment to looking after the whole person, rather than focusing only on the condition that first brought them to the clinic.

Some inherited conditions increase susceptibility to both breast and bowel cancer. However, having one does not automatically mean that everyone is at increased risk of the other. Personal history, family history and, where indicated, genetic assessment help us decide who needs additional surveillance.

Alcohol provides another important connection between these two cancers, and an opportunity to discuss a risk we can modify.

An article I read earlier this year highlighted research suggesting that drinking more than two glasses of wine a day could raise bowel cancer risk by 25%.

But what does that figure actually mean? Does the type of drink matter? And if you have been drinking regularly for years, is there still a benefit in changing?

The answers deserve more than a headline.

What did the research find?

The study, published in Cancer in early 2026, followed approximately 88,000 American adults, among whom 1,679 developed colorectal cancer over approximately 20 years.

Participants reported their drinking during different periods of adulthood, allowing researchers to explore lifetime exposure rather than simply recent consumption.

Among current drinkers, those averaging 14 or more alcoholic drinks a week across adulthood had approximately 25% higher relative risk of colorectal cancer than those averaging about one drink a week or less.

Consistently heavy drinking throughout adulthood was associated with approximately 91% higher relative risk compared with consistently light drinking.

These findings are important, but they need careful interpretation.

A higher risk is not a prediction

A 25% increase in relative risk does not mean that 25 out of every 100 people drinking at that level will develop bowel cancer.

For illustration only, if a group’s underlying risk over a particular period were four in 100, a 25% relative increase would make it approximately five in 100. This is a hypothetical example, not a personal risk estimate.

The study was observational. Participants had to recall past drinking, and other lifestyle differences could not be completely excluded. It cannot establish that alcohol alone caused the precise increases observed.

Nevertheless, the wider evidence already establishes alcohol as a cause of bowel cancer and several other cancers.

A glass is not a reliable measure of alcohol. Its size, the amount poured and the drink’s strength all matter.

For context, a US standard drink contains 14 grams of alcohol, roughly the amount in 150 ml of wine at 12% alcohol. A generous home pour or a stronger wine may contain considerably more. A pint of beer is not automatically equivalent to one standard drink either.

The study’s threshold should not be interpreted as a dividing line below which drinking is harmless.

The relevant exposure is the alcohol itself, not whether it comes in a wine glass, beer bottle or cocktail. Red wine is not exempt from alcohol-related cancer risk.

How can alcohol contribute to cancer?

When the body breaks down alcohol, it produces acetaldehyde, a harmful chemical that can damage DNA. Alcohol can also promote oxidative damage and interfere with nutrients involved in healthy cell function.

Alcohol can raise oestrogen levels, which is one mechanism through which it may increase breast cancer risk.

The concern extends beyond the breast and bowel. Alcohol also causes cancers of the mouth, throat, voice box, oesophagus and liver.

This is not simply a liver-health issue.

Beyond cancer: the brain and the rest of the body

Cancer is only part of the picture.

Long-term heavy drinking can affect memory, thinking and judgement. In older adults, alcohol misuse is associated with faster cognitive decline. This does not mean that an occasional drink inevitably causes dementia, but regular drinking should not be assumed to protect the ageing brain.

Alcohol can also disrupt sleep, worsen anxiety or depression, contribute to liver disease and increase the risk of falls and injuries. Heavier drinking can raise blood pressure, damage the heart muscle and increase the likelihood of abnormal heart rhythms.

As we age, we may become more sensitive to alcohol’s effects, while interactions with medicines become an additional concern.

Reducing alcohol is therefore about more than cancer prevention. It is also an opportunity to protect day-to-day wellbeing, independence and long-term health.

Is it too late to change?

A long history of drinking is not a reason to give up on prevention.

The study offered an encouraging finding: former drinkers had lower odds of certain non-advanced adenomas, which are polyps that can sometimes precede cancer, compared with current light drinkers.

However, this does not prove that stopping alcohol immediately reverses bowel cancer risk. The evidence on cessation was limited, and the study cannot tell an individual how quickly their risk might change.

The practical message remains positive: your past habits do not have to determine your next steps. Reducing alcohol exposure remains a worthwhile investment in health.

Making change manageable

Rather than approaching this with guilt, consider a practical review:

• Record what you drink for a week, including home pours and weekend drinks.

• Measure rather than guess, noting serving size and alcohol strength.

• Plan alternatives for occasions when drinking has become automatic.

• Avoid saving up drinks for one evening. Drinking heavily on a single occasion carries its own risks.

• Ask for support if cutting down feels difficult or alcohol has become a way to cope.

These are starting points for a conversation, not a test of willpower.

An important safety note: if you may be dependent on alcohol, particularly if delaying a drink causes shaking, sweating, nausea or anxiety, seek medical advice before stopping or sharply reducing your intake. Alcohol withdrawal can be dangerous and may require supervised treatment.

Do not overlook bowel screening

Reducing alcohol is only one part of prevention. Screening provides another opportunity to protect bowel health, even when you feel entirely well.

In Hong Kong, the Government’s Colorectal Cancer Screening Programme subsidises screening for eligible people aged 50 to 75 who do not have symptoms and meet the programme’s other criteria.

Screening begins with a faecal immunochemical test (FIT) to look for hidden blood in the stool. If the result is negative, screening is generally repeated two years later. A positive result leads to referral for colonoscopy. It does not itself mean cancer has been diagnosed.

Colonoscopy is also an established screening option outside this FIT-based pathway. People with a strong family history, previous polyps or an inherited predisposition may need a different starting age or surveillance schedule.

The right approach should reflect your individual circumstances, not simply your age.

Symptoms should not wait for screening

Seek medical advice for:

• Blood in the stool or rectal bleeding.

• A persistent change in bowel habits.

• Unexplained weight loss.

• Persistent abdominal pain.

• Unexplained anaemia or ongoing fatigue.

These symptoms can have causes other than cancer, but they deserve assessment.

Do not wait for your next screening test if symptoms develop. Screening is intended for people without symptoms. New symptoms require a diagnostic assessment.

This research should prompt reflection, not panic, and certainly not blame.

Cancer is complex. Nobody should feel that a diagnosis is a personal failure. My aim is to help patients make informed choices, without fear or embarrassment.

I personally advocate colonoscopy as a primary tool for colorectal cancer prevention in appropriately selected patients from aged 40-years onward (unless there is a significant family history in first degree relatives, in which aged 35-years), not simply as a means of finding cancer once it has developed.

Its particular strength is the opportunity to inspect the bowel lining and identify and remove precancerous polyps during the same procedure.

These polyps are not yet cancers. However, some, particularly adenomas and certain serrated lesions, have the potential to become cancerous as further genetic changes accumulate within their cells. These are changes within the polyp itself and do not necessarily imply an inherited condition.

Not every polyp will progress. Nevertheless, removing precancerous lesions offers an opportunity to interrupt that process before cancer develops.

I recognise that colonoscopy is invasive. It requires bowel preparation, involves sedation, and carries small but important risks, including bleeding and bowel perforation. It also places demands on patients’ finances / insurance, clinical manpower and healthcare resources. These considerations deserve an honest discussion.

In my practice, I routinely offer colonoscopy to all my patients as the foundation of a colorectal cancer prevention programme that I have been running for 29 years. The decision to proceed follows a discussion of the benefits, risks and the patient’s individual circumstances.

In my programme, where the median patient age is 49, I have identified precancerous polyps in approximately 27% of patients. For me, this underlines the importance of discussing prevention while people feel well, rather than waiting for symptoms.

My experience has been particularly encouraging: no patient who has remained on the programme and continued the recommended surveillance has subsequently developed colorectal cancer. This is an observation from my own practice, rather than a guarantee of what any screening programme can achieve.

The purpose is not simply to find cancer earlier. It is to identify and remove precancerous polyps before they have the opportunity to develop into cancer, and to continue surveillance for further lesions.

I recognise that colonoscopy is invasive and requires bowel preparation. It carries procedural risks and has financial implications for patients, as well as demands on clinical staff and healthcare resources. These considerations deserve an honest discussion. Nevertheless, my experience has made me a strong advocate for this proactive approach.

My emphasis is on prevention through both polyp removal and continued follow-up, not reassurance from a single examination.

What I would like patients to understand is the distinction between detecting cancer early and preventing some cancers from developing in the first place. Colonoscopy with appropriate polyp removal can contribute to both.

During Breast Cancer Awareness Month, this broader approach to prevention feels especially relevant. We should not view breast health, bowel health and everyday habits as entirely separate conversations.

My advice is to look honestly at your drinking, share your family’s cancer history with your doctor, and discuss the screening approach that is right for you.

Know what is in your glass. Know your family history. And make prevention a conversation before symptoms make it a necessity.

Disclaimer: This newsletter provides general information, not individual medical advice. Please consult your doctor about alcohol reduction, bowel symptoms, genetic risk or an appropriate screening plan.

Source

More than two glasses of wine a day raises bowel cancer risk by 25%

By Eleanor Hayward

Having more than two glasses of wine a day increases the risk of developing bowel cancer by 25 per cent, research suggests.

Scientists looked at data from 88,000 adults in the US and found that drinking heavily from the age of 18 onwards significantly increased the risk of the disease. Heavy drinking was defined as having at least 14 alcoholic drinks per week, such as pints of beer, glasses of wine or gin and tonics.

The research involved scientists from the University of Maryland and Queen’s University Belfast, who found that cancer risk increased the more people drank throughout their lives.

They asked adults aged 55 and over how much they drank each week. They were also asked to recall how much they had drunk at younger ages: between 18 and 24, 25 to 39, and 40 to 54.

The participants were followed for 20 years, during which time 1,679 of them were diagnosed with bowel cancer. Those who had more than 14 drinks a week on average were 25 per cent more likely to get the disease than people who had less than one drink. If people had consistently been heavy drinkers at all phases of adult life since the age of 18, then the risk increased to 91 per cent.

However, the study found that it was never too late to stop drinking as the heightened risk dropped if people no longer drank alcohol in their fifties and sixties, even if they had drunk a lot of alcohol as younger adults.

Bowel cancer is the second biggest cancer killer in the UK, with 44,000 cases and 16,000 deaths each year.

The study author Dr Erikka Loftfield, of the US National Cancer Institute, said: “Our study is one of the first to explore how drinking alcohol over the life course relates to both colorectal adenoma and colorectal cancer risk. While the data on former drinkers were sparse, we were encouraged to see that their risk may return to that of the light drinkers.”

One in 25 cases of cancer in the UK — about 17,000 each year — are caused by alcohol, research shows. Alcohol can cause seven types of cancer, including breast and bowel.

There are several reasons alcohol can cause cancer, including by converting to a toxic chemical called acetaldehyde, which damages cell DNA. Alcohol also changes cells in the mouth, making it easier for them to absorb harmful chemicals.

It also can increase levels of the hormone oestrogen, which can fuel the development of breast cancer.

The World Cancer Research Fund, a charity based in London, has said bottles of wine and beer should have warning labels stating that alcohol causes cancer.

It is running a campaign urging the government to require companies to put “bold and unambiguous” health warnings and calorie information on alcoholic drinks.

It is also calling for minimum alcohol pricing of 65p per unit in England, the level already in force in Scotland, as well as marketing and advertising restrictions on alcoholic drinks.